Circuit arrangement for generating a supply voltage with controllable ground potential level

Abstract

A circuit arrangement for generating a supply voltage with a controllable ground potential level includes a voltage source that provides the supply voltage ungrounded, a control unit that generates an adjustable control d.c. voltage to ground, and an operational amplifier that is connected via its voltage supply terminals to the supply voltage source, where the control d.c. voltage is applied to the inverting input of the operational amplifier, the non-inverting input of the operational amplifier is connected via a resistor network to the voltage source and to a ground terminal and the output of the operational amplifier is fed back to the inverting input via a capacitor.

What is claimed is: 
     
       1. A circuit arrangement for generating a supply voltage with a controllable ground potential level, the circuit arrangement comprising:
 a voltage source which provides the supply voltage ungrounded as a difference between two supply voltage potentials; 
 a control unit which generates an adjustable control d.c. voltage to ground; and 
 an operational amplifier having voltage supply terminals connected to the supply voltage potentials of the voltage source, the adjustable control d.c. voltage being applied to an inverting input of the operational amplifier, a non-inverting inverting input of the operational amplifier being connected via a resistor network to the supply voltage potentials of the voltage source and to a ground terminal and an output of the operational amplifier being fed back to the inverting input via a capacitor. 
 
     
     
       2. The circuit arrangement as claimed in  claim 1 , wherein the control unit is configured to generate the adjustable control d.c. voltage as an average value of at least two individually activatable and deactivatable fixed voltages. 
     
     
       3. The circuit arrangement as claimed in  claim 1 , further comprising:
 a resistor connected in series with the capacitor between the output of the operational amplifier and the inverting input of the operational amplifier. 
 
     
     
       4. The circuit arrangement as claimed in  claim 1 , further comprising:
 a resistor connected in series with the capacitor between the output of the operational amplifier and the inverting input of the operational amplifier. 
 
     
     
       5. The circuit arrangement as claimed in  claim 1 , wherein the supply terminals of the operational amplifier are connected to the supply voltage potentials of the voltage source via Zener diodes. 
     
     
       6. The circuit arrangement as claimed in  claim 1 , wherein the voltage source is configured as a d.c. to d.c. converter with electrical isolation of input and output sides. 
     
     
       7. The circuit arrangement as claimed in  claim 1 , further comprising:
 a differential amplifier having voltage supply terminals, the differential amplifier being connected via the voltage supply terminals to the supply voltage potentials of the voltage source and being further connected to the ground terminal.